Method of transporting babies in a heated incubator

ABSTRACT

An incubator for transporting babies while keeping them, during the transportation, under a constant ambient temperature is thermally insulated on all sides and comprises in the interior receptacles containing a chemical compound preferably tetradecyl alcohol having a melting temperature between 30*-40*C and emitting latent heat when cooling down and crystallizing, this emitted heat being sufficient to compensate heat losses during transportation of the incubator and so to maintain the inner temperature for a certain time without heat supply. Before the transportation the chemical substance is melted by means of an electric heating device supplied from the outside and a thermostat keeps the inner temperature, before the transportation, slightly above the melting point of the substance.

7 United States Patent Franz et a1.

METHOD OF TRANSPQRTING BABIES IN A HEATED INCUBATOR I Inventors: Wolfgang Franz, Lubeck; Jens Stallbaum, Lubeck-Moisling, both of Germany Assignee: Dragerwerk AG, Germany Filed: May 9, 1974 Appl. No.: 468,363

Related US. Application Data Division of Ser. No. 391.134, Aug. 24, 1973. Pat. No. 3,876,859.

Foreign Application Priority Data Aug. 25, 1972 Germany"; 2241937 References Cited UNITED STATES PATENTS 7/1950 Feldman 1 ..126/400 7/1950 Kenyon ..2l9/52l [451 Nov. 11, 1975 Primary E.\'aminerRichard A. Gaudet Assistant E.\'aminerLee S. Cohen Attorney, Agent, or FirmMcG1ew and Tuttle [57] ABSTRACT An incubator for transporting babies while keeping them, during the transportation, under a constant ambient temperature is thermally insulated on all sides and comprises in the interior receptacles containing a chemical compound preferably tetradecyl alcohol having a melting temperature between 30-40C and emitting latent heat when cooling down and crystallizing, this emitted heat being sufficient to compensate heat losses during transportationof the incubator and so to maintain the inner temperature for a certain time without heat supply. Before the transportation the chemical substance is melted by means of an electric heating device supplied from the outside and a thermostat keeps the inner temperature, before the transportation, slightly above the melting point of the substance.

3 Claims, 2 Drawing Figures I/ II l 1/ l/ I US. Patent Nov. 11, 1975 3,918,432

T/ME

FIG.

2am read/viz FIG. 2

METHOD OF TRANSPORTING BABIES IN A HEATED INCUBATOR 1 This is a division of application Ser. No. 39 l l 34 filed Aug. 24, 1973, now US. Pat. No. 3,876,859.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates in general to incubators for babies and in particular to a new and useful method of keeping the temperature in the incubator constant during transportation of the baby without heat supply from the outside or from a special heating device, by placing in the incubator a chemical substance which, after being heated up above its melting temperature, harmless to the baby, cools down and solidifies under emission of latent heat, whose quantity is sufficient to compensate heat losses in the incubator during transportation. The device for carrying out this method comprises receptacles for the substance, a heating means for melting the substance and a temperature control means for maintaining the substance in a molten state before the transportation.

2. Description of the Prior Art For the transportation of prematurely bom or sick babies there are used so-called transport incubators which substantially serve to prevent a baby, during the transportation, from becoming cool. The mostly closed rest space of the baby is heated. The following designs are known: v One type of transport incubator is provided with an electric heating which is supplied by current from the network of the ambulance car. Because the output capacity ofambulance car networks is but limited, only a relatively small electric power can be withdrawn which is frequently insufficient, for example, in winter or when large transport incubators, such as used for the transfer of intensive care cases, are involved.

It is further known to connect electrically heated transport incubators to storage batteries which must be carried along. Here once more, only a small electric power is available. Also, storage batteries are heavy and hinder the transportation.

Finally, known transport incubators are provided with tanks which are filled with water which has been pre-heated or heated up before the transportation. A disadvantage is the troublesome handling of such devices. The water must be heated up to the right temperature and filled in. This work is also time consuming. It is moreover disadvantageous that after putting the device into service, the temperature continues to slowly decrease. A new heat supply is possible, only after discharging the tanks and refilling them with heated water.

That is why the problem arose to provide a method and a device avoiding the above mentioned drawbacks in which the inside of the incubator can be kept, during a longer period of time, at an approximately constant temperature irrespective of power supply.

SUMMARY OF THE INVENTION In accordance with the present invention, there is provided an improved method using a thermally insulated incubator adapted for transportation, in which a chemical substance is placed which is capable of melting at a temperature harmless to the baby and of cooling down and solidifying by emitting latent heat owing to chemical and/or physical changes of its constitution,

the heating up of the substance slightly above the melting temperature being effected before the transportation, during a preparation time, and the substance cooling down during the transportation. Thus, the temperature within the incubator can be held at a approximately constant level which is equal to or slightly below the melting temperature of the substance. The incubator used to carry out this method is provided with a heat insulation on all sides and comprises a heating device powered during the time the incubator is prepared for service, from the outside, with receptacles for the chemical substance and preferably a thermostat for keeping the temperature of the substance slightly above the melting point during the preparation time. The invention has the advantage that the service conditions of the incubator are prepared before the transportation, at'a location where heating power is available from a network, whereupon the power is cut off because it is no longer necessary for maintaining the service conditions for the relatively long time of the transportation. The incubator is independent of any supply from the outside and keeps the inner temperature constant or approximately constant in spite of the heat losses to which the outside of the incubator is exposed.

In a simple embodiment of the invention, a substance is used having a melting point between 30 and 40C. When such a substance, for example, a salt, is located within the incubator and heated up to temperature above the melting point and the incubator is closed, the temperature in the interior of the incubator first decreases to the melting temperature of the substance. After a further heat loss through .the outer walls of the incubator, the substance begins to crystallize while releasing latent heat by which the temperature in the interior of the incubator is kept approximately constant until the whole molten substance is solidified.

Advantageously, an incubator is used which is provided with a heating insulation on all sides.

According to a development of the invention, the incubator may be provided with an electric heating. This heating is used to heat up the incubator, along with the substance located therein to a temperature above the melting point of the substance, in an emplacement where the preparation is made. ,1

According to another feature of the invention, th electric heating may be located in the intermediate space between the substance or a substance receptacle and the wall of the incubator.

Also, the incubator may be provided with a thermostat by which the temperature of the substance in the preparatory state is held above the melting point.

The substance used may be hydrated sodium hydro- I gen phosphate Na HPO 12 B 0, or tetradecyl alcohol C I-I O. The latter substance has the advantage of having a defined temperature of solidification depending upon the percentage purity.

Accordingly, it is an object of the invention to provide a method for transporting babies placed in an incubator under" controlled temperature conditions in which the temperature within the incubator is kept constant without heat supply from the outside by permitting the cooling and solidification of a substance in the incubator whose melting temperature is harmless to the baby and which while solidifying emits latent heat so as to compensate the heat losses during transportation.

Another object of the invention is to provide an incubator adapted to carry out this method and therefore comprising receptacles for the substance to be melted and subsequently cooled down, heating means, preferably an electrical heating device powered from the outside for melting the substance during the preparation time, before the transportation, and temperature controlling means preferably a thermostat for maintaining the temperature of the substance during the preparation time slightly above the melting point.

Another object of the invention is to provide a substance having the desiredproperties, i.e. melting temperature between 30 and 40C and the capacity of emitting latent heat while solidifying sufficient to compensate the heat losses in the incubator during transportation.

A further object of the invention is to provide an incubator which is simple in design, rugged in construction and economical to manufacture.

For an understanding of the principles of the invention, refere nce is made to the following description of a typical embodiment thereof as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the Drawings:

FIG. 1 is a longitudinal sectional view of an incubator constructed according to the invention; and

FIG. 2 is a temperature-time variation curve within the incubator ofFIG. 1.

GENERAL DESCRIPTION OF THE PREFERRED EMBODIMENT In a thermally well insulated housing or transport incubator receptacle 1,a baby 3 is received laying on a support or mattress 2. A container 6 is located in the interior of the transport incubator and filled with a substance 6a having a melting point at approximately 30-40C. A flat electric heater is connected to electrical supply terminals 7 and it is placed at least between the heat insulation layer of end walls 4a and 4b of the receptacle 1 and the container 6. With the aid of this heating, the container 6 is heatedduring the preparation time until the substance 60 is melted. By means "er a thermostat 8 the temperature of the substance to be melted is held at a level slightly above the melting point.

FIG. 2 shows the temperature variation as a function of time, it being assumed that at the time a the incubator is heated up to a predetermined temperature I. The preparation time ends at b. At this moment, the power supply of the electric heater 5 is cut off.

After placing the baby in the incubator, the transportation takes place and. the temperature within the hem bator drops to a value t, corresponding to the melting temperature of the substance. The substance begins to solidify. Latent heat of solidification is released which,

as shown in FIG. 2, keeps the temperature in the receptacle l constant in spite of the continuing heat dissipaaccomplished. Provided that the interior surface of the container 6 is large as compared to the non-heated inner surfaces of the transport incubator and that the non-heated inner surfaces of the transport incubator are thermally well insulated to the outside, an incubator temperature is produced which is close below the solidification temperature of the molten substance in the container 6 and which is only little influenced by the outer ambient temperature. In consequence, during the transportation, the keeping of the temperature is independent of a power supply from the outside; the temperature in the interior of the incubator largely corresponds to the temperature of the molten substance in the container 6 which remains constant for a long time in spite of the heat dissipation.

Only at the time c after the whole molten substance in the'container6 is solidified, the transport incubator begins to slowly cool down to the ambient temperature While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

l. A method of transporting babies to be held under controlled temperature conditions in a comfort temperature range of the infant comprising providing a transportable incubator without any power source and which has an infant receiving compartment, placing a substance within the compartment which is harmless to babies and which has a melting temperature in the comfort temperature range of the infant and is capable of emitting heat to the compartment whenever it is subjected to temperatures below its melting temperature, placing a heater in the compartment adjacent the substance heating the substance during a preparation time to a temperature above its crystallization temperature by connecting the heater to an exterior heating source, and keeping the temperature within the compartment during the preparation time above the melting point of the substance, placing the baby in the compartment, stopping the heating of the interior of the compartment by disconnecting the exterior heating source and closing the compartment, transporting the incubator with the infant while permitting the substance to heat the interior of the compartment during transportation time without any heat supply by giving up its latent heat by solidification whenever the temperature in the compartment tends to lower below the melting temperature of the substance.

2. A method of transporting babies according to claim 1, wherein said substance is hydrated sodium hydrogen phosphate Na, HPO, 12 B 0.

3. A method of transporting babies according to claim 1, wherein said substance is tetradecylalcohol C14H300. 

1. A method of transporting babies to be held under controlled temperature conditions in a comfort temperature range of the infant comprising providing a transportable incubator without any power source and which has an infant receiving compartment, placing a substance within the compartment which is harmless to babies and which has a melting temperature in the comfort temperature range of the infant and is capable of emitting heat to the compartment whenever it is subjected to temperatures below its melting temperature, placing a heater in the compartment adjacent the substance heating the substance during a preparation time to a temperature above its crystallization temperature by connecting the heater to an exterior heating source, and keeping the temperature within the compartment during the preparation time above the melting point of the substance, placing the baby in the compartment, stopping the heating of the interior of the compartment by disconnecting the exterior heating source and closing the compartment, transporting the incubator with the infant while permitting the substance to heat the interior of the compartment during transportation time without any heat supply by giving up its latent heat by solidification whenever the temperature in the compartment tends to lower below the melting temperature of the substance.
 2. A method of transporting babies according to claim 1, wherein said substance is hydrated sodium hydrogen phosphate Na2 HPO4 . 12 H2O.
 3. A method of transporting babies according to claim 1, wherein said substance is tetradecylalcohol C14H30O. 